Differences in gynecologic tumor development in Amhr2-Cre mice with KRASG12D or KRASG12V mutations

Eucharist H S Kun,Joanne S Richards,Anais Malpica,Sophia Pan,David M Gershenson,Tejas Medapalli,Sophia Lin,Kwong-Kwok Wong,Yvonne T M Tsang

doi:10.1038/s41598-020-77666-y

Eucharist H S Kun, Joanne S Richards + Show 7 more

Open Access

https://doi.org/10.1038/s41598-020-77666-y

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Abstract

How different KRAS variants impact tumor initiation and progression in vivo has not been thoroughly examined. We hypothesize that the ability of either KRASG12D or KRASG12V mutations to initiate tumor formation is context dependent. Amhr2-Cre mice express Cre recombinase in tissues that develop into the fallopian tubes, uterus, and ovaries. We used these mice to conditionally express either the KRASG12V/+or KRASG12D/+ mutation. Mice with the genotype Amhr2-Cre Pten(fl/fl) KrasG12D/+(G12D mice) had abnormal follicle structures and developed low-grade serous ovarian carcinomas with 100% penetrance within 18 weeks. In contrast, mice with the genotype Amhr2-Cre Pten(fl/fl) KrasG12V/+ (G12V mice) had normal follicle structures, and about 90% of them developed uterine tumors with diverse histological features resembling those of leiomyoma and leiomyosarcoma. Granulosa cell tumors also developed in G12V mice. Differences in cell-signaling pathways in the uterine tissues of G12D and G12V mice were identified using RNA sequencing and reverse-phase protein array analyses. We found that CTNNB1, IL1A, IL1B, TNF, TGFB1, APP, and IL6 had the higher activity in G12V mice than in G12D mice. These mouse models will be useful for studying the differences in signaling pathways driven by KrasG12V/+ or KrasG12D/+ mutations to aid development of targeted therapies for specific KRAS mutant variants. Our leiomyoma model driven by the KrasG12V/+ mutation will also be useful in deciphering the malignant progression from leiomyoma to leiomyosarcoma.

Highlights

Activating KRAS mutations are found in more than 20% of all human cancers, including low-grade serous ovarian carcinoma, lung carcinoma, pancreatic cancer, endometrial cancer, and colorectal carcinoma[1,2,3,4,5,6]
Another study found that, in isogenic MCF10A cell lines with different KRAS mutations, KRAS G12V has a higher level of GTP-bound KRAS and slightly greater anchorage-independent growth associated with more aggressive phenotype than the KRAS G12D and the wild-type variants[29]
Using Amhr2-Cre P tenfl/fl mice, we demonstrated that both conditionally expressed KRAS G12V and G12D mutants could activate the MAPK pathway but have different functional impacts on the pathogenesis of epithelial cells on the ovarian surface, granulosa cells, and uterine mesenchymal cells

Summary

Introduction

Activating KRAS mutations are found in more than 20% of all human cancers, including low-grade serous ovarian carcinoma, lung carcinoma, pancreatic cancer, endometrial cancer, and colorectal carcinoma[1,2,3,4,5,6]. Another study found that, in isogenic MCF10A cell lines with different KRAS mutations, KRAS G12V has a higher level of GTP-bound KRAS and slightly greater anchorage-independent growth associated with more aggressive phenotype than the KRAS G12D and the wild-type variants[29]. We hypothesized that the ability of the KRASG12D or KRASG12V mutations to initiate tumor formation would be context dependent as suggested by a previous s tudy[32] In this previous study, when KRASG12V was activated throughout the whole body at a postnatal stage, only a percentage of KRASG12V-expressing lung bronchiolo-alveolar cells became multiple adenomas and adenocarcinomas and no other tumor types were observed[32]. To discover the cellular pathways or the cellular context of a specific cell type to KRAS induced tumor development will provide insights into the mechanisms on how malignant transformation occurs in vivo

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